by Robert Alison

The Rosellas (Platycercus sp.) comprise an extraordinarily colourful and intelligent complex of Australian psittacids whose evolutionary development is compelling and complicated. Sophisticated genetic sequencing research at the University of New South Wales indicates all Rosellas probably derived from a single ancestral type 18-143 million years ago. The divergence was apparently quite slow.

Eventually, geographically distinct sub-populations developed. The inter-relationships among those sub-groups have been the focus of substantial scientific investigation that, so far, has disclosed some perplexing anomalies.

One of the most intriguing findings concerns the so-called ‘ring’ species - the P. elegans group whose rare evolutionary path has sparked a great deal of scientific scrutiny. “Ring species are reproductively isolated forms connected by a chain of intermediate populations,” according to researchers Daren and Jessica Irwin and Trevor Price.

Read more in the magazine…